The present invention relates to a solid electrolytic capacitor.
A typical solid electrolytic capacitor is manufactured by anodizing an anode, which is made of a valve metal such as niobium (Nb) and tantalum (Ta), to form a dielectric layer including mainly oxides on the surface of the anode. Then, an electrolyte layer is formed on the dielectric layer, and a cathode layer is formed on the electrolyte layer. Japanese Laid-Open Patent Publication No. 4-48710 describes an electrolyte layer formed by superimposing a first conductive polymer layer of polypyrrole formed through chemical polymerization onto a second conductive polymer layer of polypyrrole formed through electrolytic polymerization.
With such a solid electrolytic capacitor in the prior art, when the dielectric layer includes a defect (for example, crystallization of an amorphous dielectric layer), leakage current may increase. To reduce leakage current, the thickness of the dielectric layer may be increased. However, this would decrease the capacitance. It is thus required that such characteristics of solid electrolytic capacitors be improved.